I just purchased a Curve from AT&T and on a whim tried to set up my business account to work with the phone. Much to my surprise it worked. I am pretty sure we are using BES at the office, but even if we are I was shocked that it configured on my Curve seeing that my data plan is not supposed to support it. Should I expect to see a huge bill if I keep this email address on the phone because I have the personal plan and not the business?

Congratulations on the new Curve.
Weather or not you should expect to see a huge bill will depend on two different things:
1 - How much data per month you are allowed on your plan
2 - How much data (emails, web browsing, etc)that you do per month.

Once you know those you'll know the effect.
If it doesnt cost you extra to change your plan you may want to get the unlimited for a month and review your bill afterwards and change appropriately. It may cost you less in the long run.

Well, I have the Blackberry personal unlimited data plan already. The only difference that I see is that the personal version says "can not be used with blackberry enterprise server". Does this mean that it will not work, or just that I will get killed on the bill if I do use it. There is a possibility that we are not running BES at the office, but I have no idea.

Well, I have the Blackberry personal unlimited data plan already. The only difference that I see is that the personal version says "can not be used with blackberry enterprise server". Does this mean that it will not work, or just that I will get killed on the bill if I do use it. There is a possibility that we are not running BES at the office, but I have no idea.

okey you have a BIS plan not BES. If you want your plan to support your office/works email switch your plan to BES.

So I guess that brings me back to my original question, I guess I was not clear in the first place. If the curve says that it can recognize my work email with the current plan I have, that means I am not using BES correct?

So I guess that brings me back to my original question, I guess I was not clear in the first place. If the curve says that it can recognize my work email with the current plan I have, that means I am not using BES correct?

IF you can receive/send your work email add using "personal plan" your company does not use BES. Therefore you do not have a BES plan either

To be clear just call your provider and ask if you have BIS or BES. You can also contact your IT and ask if your company is running BES

I would contact IT, but the problem is I don't trust our guy all that much with this stuff. Also, I have a work blackberry already just wanted to see if I could get this one to work with the same emails as well so I don't have to carry the other one.

I would contact IT, but the problem is I don't trust our guy all that much with this stuff. Also, I have a work blackberry already just wanted to see if I could get this one to work with the same emails as well so I don't have to carry the other one.

As I understand it, if you are on BES, your company would need to provision the new Blackberry as a separate device to be recognized by the company servers. I believe those kinds of things are device-specific (meaning they need the PIN), not email address-specific.